An Experimental and Modelling Approach to Engineering the Stability of Mixed Micro- and Nano-Grain Size Polycrystals to Improve Durability

Abstract

The focus of this research proposal is to understand and control fracture processes in anomalous bimodal grain sized microstructures in the micro to nano regime of selected fcc, bcc and hcp metals and alloys. The idea has been stimulated by previous work which showed that coarse grains arising from anomalous grain growth in a nanoscale grain matrix improved ductility with little strength-loss penalty. It is therefore worthwhile to pursue the novel endeavour of how these mixed grain distributions could influence deformation and fracture resistance. A key feature of the research strategy is that it is founded on a proven multidisciplinary approach involving a research consortium of four university groups who have individual expertise in a range of topics related to material performance. Working together has resulted in an enhanced skill set, endorsed by two previous EPSRC grants to the group.The aims of the project will be achieved by an experimental programme involving designing and characterising conditions to achieve the required anomalous growth spanning the micro to nano length scales, modelling the grain growth/fracture process, measuring the deformation and the fracture resistance of the anomalous mixed grain size materials. Regular meetings and interchange will ensure that the project benefits from the synergy within the group. The project has the enthusiastic backing of Integran Technologies Inc and British Energy Ltd (see appended letter of support).